Insertion/deletion mutations of type I oculocutaneous albinism in chinese patients from Taiwan

Type I oculocutaneous albinism (OCA1) is an autosomal recessive disorder, which is caused by the reduction or the absence of tyrosinase activity in melanocytes of the skin, hair and eyes. Although tyrosinase mutations of OCA1 have been extensively analyzed in most populations worldwide, there is no systemic study of OCA1 mutation in Chinese patients. By use of single strand conformation polymorphism and direct sequencing, we had detected 21 mutant alleles out of 24 OCA1 chromosomes screened (87.5%). Detected mutant alleles include one splicing site, three insertion/deletion and five missense mutations, of which the splicing site nucleotide alteration (IVS 1-3C>G) and two each of the insertion/deletion (232-233 ins GGG and 861-862 del TT) and missense mutations (Cys 289 Gly and Trp 400 Leu) are novel. The ins/del mutations accounts for about 37.5% in Chinese OCA1 alleles. The 232-233 ins GGG, one of the novel mutations, was found to be most frequent (25%) among the OCA1 alleles in Chinese. Through this study, we found that while some of the OCA mutant alleles were identified in other populations, ethnic difference still exists. Hum Mutat 14:542, 1999.

3-hydroxy-3-methylglutaric aciduria presenting with Reye like syndrome: report of one case

We report the case of a patient with 3-hydroxy-3-methylglutaric aciduria who presented with a repeat attack of Reye like syndrome clinically. Vomiting and somnolence, generalized tonic and clonic convulsions with hepatomegaly, hyperammonemia, liver function impairment, and mild metabolic acidosis were the presenting signs. 3-hydroxyisovaleric, 3-methylglutaric, 3-methylglutaconic and 3-hydroxy-3-methylglutaric acids were detected in the urine by gas chromatography-mass spectrometry. 3-methylglutarylcarnitine was also identified in the urine by fast atom bombardment and tandem mass spectrometry. Therefore, the possibility of metabolic disease should be considered in neonates and infants with repeat attacks of Reye like syndrome and a history of similarly affected siblings.

Plasma apolipoprotein B-48, hepatic apolipoprotein B mRNA editing and apolipoprotein B mRNA editing catalytic subunit-1 mRNA levels are altered in zinc-deficient rats

Apolipoprotein B (apoB) exists as two major isoforms and serves as an obligatory component of lipid-rich plasma lipoprotein particles. Apolipoprotein B mRNA editing is a zinc-dependent, site-specific cytidine deamination that determines whether the apoB-100 or apoB-48 isoform is synthesized. The objective of this work was to examine whether dietary zinc levels affect apoB mRNA editing in vivo. Adult male Sprague-Dawley rats were randomly assigned to zinc-deficient (ZD, <0.5 mg Zn/kg diet), zinc-adequate (ZA, 30 mg Zn/kg diet) or zinc-replenished (ZDA, ZD rats fed the ZA diet for last 2 d) dietary groups for 18 d. The ratio of plasma apolipoprotein B-48 (apoB-48) to total apoB was significantly lower in zinc-deficient compared with zinc-adequate rats. Primer extension analysis indicated a modest but significant reduction in hepatic apoB mRNA editing in ZD rats compared with that of the ZA group. In ZDA rats, hepatic apoB mRNA editing and the percentage of plasma apoB-48 to total apoB were not different from ZA rats. The mRNA abundance of hepatic apobec-1 (apoB mRNA editing catalytic subunit 1) was significantly lower in ZD and ZDA rats than in ZA rats. In summary, the plasma ratio of apoB-48 to total apoB protein as well as hepatic apoB mRNA editing and hepatic apobec-1 mRNA levels were reduced in rats consuming a zinc-deficient diet. These data suggest that one or more components of apoB metabolism may be influenced by dietary zinc status.

Epileptiform activity can be initiated in various neocortical layers: an optical imaging study

The initiation site for triggering epileptiform activity was investigated via optical imaging using voltage-sensitive dyes in the neocortical slice perfused with artificial cerebral spinal fluid containing nominally zero magnesium. The neocortical slices (400-microm thick) were harvested from Sprague-Dawley rats (P21-28). Optical imaging was made by using a high speed photodiode array. Spontaneous epileptiform activity emerged 20-40 min after the preparation was perfused with zero-magnesium solution. There was a good correspondence between electrical and optical signals (n = 46), although the details of the two recordings were somewhat different. The initiation sites were measured optically in 11 preparations. Among them, four were found to be located in superficial layers, two were found in middle layers, and five were found in deep layers. Repeated recordings revealed that these initiation sites were relatively stable; shifting of the initiation site was not observed. Therefore spontaneous epileptiform activity could be initiated in various cortical layers, from layer I to layer VI. The activation started from a small area <0.04 mm(3) and spread smoothly from the initiation site to adjacent cortical areas, suggesting that the initiation site is very confined to one of the cortical layers. The initiation sites were distributed randomly in various cortical areas, and no higher probability was found in a special cortical region. Electrical stimulation delivered via a glass microelectrode filled with 2 M NaCl (2-5 MOhms) could reliably trigger epileptiform activity that had the same characteristics as the spontaneous activity. The cortical neurons activated directly by the stimulation were around the electrode's tip and estimated to be within a 50-microm area, suggesting that only a few neurons were needed to form an initiation site. Because the timing for stimulation was arbitrary and the evoked events were initiated independent of discharges of neurons in any other layers, it is likely that the initiation site for epileptiform activity in various cortical layers is independent of the control of layer V pyramidal neurons. Together these finding suggest that the epileptiform focus is confined and can be formed in several (probably all) neocortical layers and in many cortical areas. The initiating neurons may be of different types because neuronal types in various cortical layers are different.

Fringe: defining borders by regulating the notch pathway

The Notch pathway mediates cell-cell interaction in many developmental processes. Multiple proteins regulate the Notch pathway, among these are the products of the fringe genes. The first fringe gene was identified in Drosophila, where it is involved in the formation of the dorsal/ventral border of the wing disc. It has now been found to be crucial for determining the dorsal/ventral border of the Drosophila eye. In vertebrates, fringe genes play roles in the formation of the apical ectodermal ridge, the dorsal/ventral border in the limb bud, and in the development of somitic borders. The roles of fringe in the neural tube or the eyes of vertebrate embryos are not clear, although it is unlikely that these roles are evolutionarily related to those in the same tissues in Drosophila. Genetic evidences suggest that Fringe protein functions by modulating the Notch signaling pathway, perhaps through differential regulation of Notch activation by different ligands; however, the mechanism underlying Fringe function remains to be investigated.

Apolipoprotein A-I gene expression is regulated by cellular zinc status in hep G2 cells

The influence of Zn on the expression of the apolipoprotein A-I (apoA-I) gene in Hep G2 cells was examined. Zn depletion was achieved with a low-Zn (ZD) medium prepared from Zn-free growth medium (Opti), a ZD medium containing Chelex 100-extracted fetal bovine serum (CHE), and a medium containing chelator 1, 10-phenanthroline (OP). Compared with those for their respective controls, cellular Zn levels were reduced by 55, 48, and 46% and apoA-I mRNA abundances were reduced by 20, 29, and 28% in Opti, CHE, and OP systems, respectively, after one passage in ZD media or 24 h in OP medium. To establish the specificity of Zn treatment, groups of ZD cells were treated with their respective control media for the last 24 h (ZDA) or normal cells were cultured with OP medium supplemented with Zn (OP-Zn). ZDA treatments partially normalized cellular Zn levels in the Opti system and restored or elevated apoA-I mRNA levels in the Opti or CHE system, respectively. Similarly, the OP-Zn treatment restored the cellular Zn and apoA-I mRNA levels. Furthermore, one passage of culture with Zn-supplemented media in both the Opti and CHE systems resulted in higher cellular Zn and apoA-I mRNA levels than those for controls. Most significantly, short-term high-Zn induction to normal cells markedly elevated the cellular Zn (3-fold) and apoA-I mRNA (5-fold) levels. Data derived from this study strongly suggest that the expression of apoA-I is regulated by cellular Zn status.

Rapid diagnosis of common aneuploidies by quantitative fluorescent polymerase chain reaction

The most frequent autosomal aneuploidies in newborns involve chromosomes 21, 18, and 13. The pre- and postnatal detection of chromosome abnormalities has been almost exclusively performed by cytogenetic analysis. In this paper, we assess the diagnostic value of fluorescent polymerase chain reaction (PCR) using polymorphic small tandem repeats (STR). PCR products are distinguished via both size and fluorescence intensity to confirm the trisomy by either triallelic signals with similar fluorescence intensities or diallelic pattern with double-dose response. Compared with the relatively time-consuming and laborious classic cytogenetic analysis, this technique is rapid, inexpensive, and sensitive for the detection of trisomies 21, 18 and 13, particularly when the numbers of cells obtained from the prenatal diagnosis is limited or where cell culture fails. With greater samples tested and more STR markers available, this method will become more reliable. This study investigates the detection of aneuploides involving chromosomes 21, 18, and 13 by comparing quantitative fluorescent PCR with karyotyping performed by conventional cytogenetics. The results obtained by the two techniques were concordant in all trisomy cases of this study.

Transcription repression by Xenopus ET and its human ortholog TBX3, a gene involved in ulnar-mammary syndrome

T box (Tbx) genes are a family of developmental regulators with more than 20 members recently identified in invertebrates and vertebrates. Mutations in Tbx genes have been found to cause several human diseases. Our understanding of functional mechanisms of Tbx products has come mainly from the prototypical T/Brachyury, which is a transcription activator. We previously discovered ET, a Tbx gene expressed in Xenopus embryos. We report here that ET is an ortholog of the human Tbx3 and that ET is a repressor of basal and activated transcription. Functional dissection of the ET protein reveals a novel transcription-repression domain highly conserved among ET, human TBX3, and TBX2. These results reveal a new transcription repressor domain, show the existence of a subfamily of transcription repressors in the Tbx superfamily, and provide a basis for understanding etiology of diseases caused by Tbx3 mutations.

Role of synaptic vesicle proton gradient and protein phosphorylation on ATP-mediated activation of membrane-associated brain glutamate decarboxylase

Previously, we have shown that the soluble form of brain glutamic acid decarboxylase (GAD) is inhibited by ATP through protein phosphorylation and is activated by calcineurin-mediated protein dephosphorylation (Bao, J., Cheung, W. Y., and Wu, J. Y. (1995) J. Biol. Chem. 270, 6464-6467). Here we report that the membrane-associated form of GAD (MGAD) is greatly activated by ATP, whereas adenosine 5'-[beta,gamma-imido]triphosphate (AMP-PNP), a non-hydrolyzable ATP analog, has no effect on MGAD activity. ATP activation of MGAD is abolished by conditions that disrupt the proton gradient of synaptic vesicles, e.g. the presence of vesicular proton pump inhibitor, bafilomycin A1, the protonophore carbonyl cyanide m-chorophenylhydrazone or the ionophore gramicidin, indicating that the synaptic vesicle proton gradient is essential in ATP activation of MGAD. Furthermore, direct incorporation of (32)P from [gamma-(32)P]ATP into MGAD has been demonstrated. In addition, MGAD (presumably GAD65, since it is recognized by specific monoclonal antibody, GAD6, as well as specific anti-GAD65) has been reported to be associated with synaptic vesicles. Based on these results, a model linking gamma-aminobutyric acid (GABA) synthesis by MGAD to GABA packaging into synaptic vesicles by proton gradient-mediated GABA transport is presented. Activation of MGAD by phosphorylation appears to be mediated by a vesicular protein kinase that is controlled by the vesicular proton gradient.

The mouse SLIT family: secreted ligands for ROBO expressed in patterns that suggest a role in morphogenesis and axon guidance

The Slit gene encodes a secreted molecule essential for neural development in Drosophila embryos. Here we report the identification of three Slit homologues in the mouse. We demonstrate that the mouse SLIT1 protein can bind ROBO1, a transmembrane receptor implicated in axon guidance. Both whole-mount and section in situ hybridization studies reveal unique and complementary patterns of expression of the three mouse Slit genes and of Robo1, both within the central nervous system and in other developing tissues. The complementary expression patterns of Slit and Robo1 and their in vitro interaction suggest a ligand-receptor relationship. The expression of all three Slit genes in the floor plate suggests that they are likely to share the same functional properties with their Drosophila homologue in midline neural development and axon guidance. The complementary expression of Slit and Robo1 in different subdivisions of the somites suggests their possible function in axon pathfinding and neural crest cell migration. The unique expression pattern in limb and other organs indicates additional potential functions of the Slit gene family.

Directional guidance of neuronal migration in the olfactory system by the protein Slit

Although cell migration is crucial for neural development, molecular mechanisms guiding neuronal migration have remained unclear. Here we report that the secreted protein Slit repels neuronal precursors migrating from the anterior subventricular zone in the telencephalon to the olfactory bulb. Our results provide a direct demonstration of a molecular cue whose concentration gradient guides the direction of migrating neurons. They also support a common guidance mechanism for axon projection and neuronal migration and suggest that Slit may provide a molecular tool with potential therapeutic applications in controlling and directing cell migration.

Microbial decolorization of azo dyes by Proteus mirabilis

A bacterium identified as Proteus mirabilis was isolated from acclimated sludge from a dyeing wastewater treatment plant. This strain rapidly decolorized a deep red azo dye solution (RED RBN). Features of the decolorizing process related to biodegradation and biosorption were also studied. Although P. mirabilis displayed good growth in shake culture, color removal was best in anoxic static cultures. For color removal, the optimal pH and temperature were 6.5-7.5 and 30-35 degrees C, respectively. The organism exhibited a remarkable color removal capability, even at a high concentration of azo dye. More than 95% of azo dye was reduced within 20 h at a dye concentration of 1.0 g L-1. Decolorization appears to proceed primarily by enzymatic reduction associated with a minor portion, 13-17%, of biosorption to inactivated microbial cells.

Cellular and molecular guidance of GABAergic neuronal migration from an extracortical origin to the neocortex

Formation of the normal mammalian cerebral cortex requires the migration of GABAergic inhibitory interneurons from an extracortical origin, the lateral ganglionic eminence (LGE). Mechanisms guiding the migratory direction of these neurons, or other neurons in the neocortex, are not well understood. We have used an explant assay to study GABAergic neuronal migration and found that the ventricular zone (VZ) of the LGE is repulsive to GABAergic neurons. Furthermore, the secreted protein Slit is a chemorepellent guiding the migratory direction of GABAergic neurons, and blockade of endogenous Slit signaling inhibits the repulsive activity in the VZ. These results have revealed a cellular source of guidance for GABAergic neurons, demonstrated a molecular cue important for cortical development, and suggested a guidance mechanism for the migration of extracortical neurons into the neocortex.

An R248C mutation of FGFR3 leading to thanatophoric dysplasia type I

Thanatophoric dysplasia (TD) is the most common form of lethal neonatal dwarfism with micromelic shortening of the limbs, macrocephaly, platyspondyly, and reduced thoracic cavity. R248C mutation in the extracellular domain of fibrobast growth factor receptor 3 (FGFR3) was common in TD type I. Two TD type I patients were examined for R248C mutation by use of restriction digestion and direct sequencing. The results showed that both patients carried R248C mutation. Because of the homogeneity of R248C mutation among different ethnic populations, all TD patients should be analysed using this PCR-based method presented in this work.

Propagating activation during oscillations and evoked responses in neocortical slices

Population activity in the cortex is poorly understood. In this report we use voltage-sensitive dye imaging to examine the spatiotemporal patterns of a 7-10 Hz oscillation in neocortical slices from rat somatosensory areas. This oscillation appeared as a component of spontaneous epochs when the preparation was bathed in low [Mg] artificial CSF (ACSF) (Silva et al., 1991). Each epoch started with a synchronized spike, and 3-200 cycles of oscillation emerged afterward. Voltage-sensitive dye imaging revealed that the oscillations in the local field potential recordings were actually caused by a propagating population activation. This activation propagated in a relatively uniform size (not expanding). We call this confined, propagating activation a "dynamic ensemble." During each oscillation cycle, one (occasionally two) dynamic ensemble(s) appeared in the slice and was sustained for 60-200 msec. Dynamic ensembles propagated at approximately 30 mm/sec; the activity could propagate in both directions in cortical slices. The propagation consisted in part of "jumps," the locations of which were not fixed. Dynamic ensembles were distinguishable from the epileptiform spikes that occurred in low [Mg] ACSF. Population events similar to dynamic ensembles were also evoked under conditions of unaltered excitability (slice in normal ACSF) by electrical stimulation that activated a low density of neurons in a large area. Our data suggest that self-sustained, spatially confined, and propagating dynamic ensembles might be related to the epoch oscillations in somatosensory cortex seen in vivo (Nicolelis et al., 1995) and thus resemble one form of population activation in the neocortex.

Mutation analysis of Wilson disease in Taiwan and description of six new mutations

Wilson disease is an autosomal recessive disorder of copper metabolism. Mutation screening in Wilson disease has led to the detection of at least 89 disease-specific mutations. Some mutations appear to be population specific, while others are common to many populations. In this study, 38 Taiwanese patients with Wilson disease were screened using single-strand conformation polymorphism analysis, followed by direct DNA sequencing. We found 12 different mutations, six of which were novel. All our detected mutations were found to be in eight exons. Four mutations in three loci (Arg778Gln, Arg778Leu, Gly943Asp, and Pro992Leu) accounted for about 58% of the mutant alleles we detected. Using an RNA transcriptional assay, we confirmed that both of our detected splice-site mutations resulted in exon skipping.

Vertebrate slit, a secreted ligand for the transmembrane protein roundabout, is a repellent for olfactory bulb axons

The olfactory bulb plays a central role in olfactory information processing through its connections with both peripheral and cortical structures. Axons projecting from the olfactory bulb to the telencephalon are guided by a repulsive activity in the septum. The molecular nature of the repellent is not known. We report here the isolation of vertebrate homologs of the Drosophila slit gene and show that Slit protein binds to the transmembrane protein Roundabout (Robo). Slit is expressed in the septum whereas Robo is expressed in the olfactory bulb. Functionally, Slit acts as a chemorepellent for olfactory bulb axons. These results establish a ligand-receptor relationship between two molecules important for neural development, suggest a role for Slit in olfactory bulb axon guidance, and reveal the existence of a new family of axon guidance molecules.

Evidence for a physical interaction between presenilin and Notch

Genetic analyses in Caenorhabditis elegans demonstrate that sel-12 and hop-1, homologues of the Alzheimer's disease-associated presenilin genes, modify signaling through LIN-12 and GLP-1, homologues of the Notch cell surface receptor. To gain insight into the biochemical basis of this genetic interaction, we tested the possibility that presenilin-1 (PS1) physically associates with the Notch1 receptor in mammalian cells. Notch1 and PS1 coimmunoprecipitated from transiently transfected human embryonic kidney 293 cell lysates in a detergent-sensitive manner, consistent with a noncovalent physical association between the two proteins. The interaction predominantly occurred early in the secretory pathway prior to Notch cleavage in the Golgi, because PS1 immunoprecipitation preferentially recovered the full-length Notch1 precursor. When PS1 was immunoprecipitated from 293 cells that had been metabolically labeled with [35S]methionine and [35S]cysteine, Notch1 was the primary protein detected in PS1 immunoprecipitates, suggesting that this interaction is specific. Furthermore, endogenous Notch and presenilin coimmunoprecipitated from cultured Drosophila cells, indicating that physical interaction can occur at physiological expression levels. These results suggest that the genetic relationship between presenilins and the Notch signaling pathway derives from a direct physical association between these proteins in the secretory pathway.

Different race, different face: minor anomalies in Chinese newborn infants

OBJECTIVE

To define the nature and incidence of minor anomalies in Chinese newborn infants and to evaluate the validity of the hypothesis that infants with three or more minor surface anomalies will also have a major malformation.

METHODS

A total of 3,345 Chinese newborn infants were examined based on a list of 67 items of minor anomalies.

RESULTS

About 44.9% of the newborn infants had at least one minor anomaly that was unrelated to gender, maternal age, or gestational age, but significantly associated with fetal presentation. Breech-presented newborn infants had double the risk of minor anomalies. Simian crease, upward slant and frontal bossing could be considered normal variants for Chinese newborn infants, because the incidence of each was higher than 4%.

CONCLUSIONS

Although some studies have shown that approximately 90% of infants having three or more minor anomalies are associated with a major malformation, we found only a 10.1% predictive value based on this study. Nevertheless, we suggest that infants with three or more minor anomalies be carefully evaluated for the possibility of major malformation in order to provide early management.

Alternative splicing and programmed cell death

Programmed cell death (PCD) is critical for development and homeostasis of multicellular organisms. Genetic and biochemical studies have revealed that PCD is under complex and delicate regulation. An important level of such regulation may be pre-mRNA splicing as suggested by the observation that a number of PCD regulatory genes are expressed as functionally distinct or even antagonistic isoforms as a result of alternative splicing. Studies on alternative splicing of these genes are reviewed here. Expression and function of a large number of genes involved in PCD are regulated by alternative splicing, including death receptors and intracellular components of the death machinery. Alternative splicing affects not only intracellular distribution but also functional activity of these death regulators, providing a fine-tuning mechanism in modulating a presumably tightly controlled process of cell death.

Molecular diagnosis of Apert syndrome in Chinese patients

Apert syndrome is a clinically distinct condition characterized by craniosynostosis and severe syndactyly of the hands and the feet. Apert syndrome results from either of two specific nucleotide substitutions, both C-to-G transversions, in the fibroblast growth factor receptor 2 (FGFR2) gene. To determine if Chinese Apert syndrome patients carry the same mutations, fifteen unrelated Apert syndrome patients and a fetus from a mother with Apert syndrome were studied by the use of restriction analysis and direct sequencing. The results demonstrated that 13 had the Ser252Trp mutation and 2 had the Pro253Arg mutation. Prenatal diagnosis of the fetus was successfully made.

Molecular diagnosis of patients with beta-thalassemia major in central Taiwan by amplified created restriction site analysis

beta-Thalassemia, a hematologic disorder characterized by the deficiency or the absence of beta-globin production, is the most widespread inherited disorder in the world; it is also common in Taiwan. We studied 38 patients in central Taiwan with beta-thalassemia major, using amplified created restriction site analysis for detection. On analysis, six different point mutations were found among 76 chromosomes, of which 32 chromosomes (42.1%) had a C to T substitution at nucleotide 654, 30 (40%) had frameshift codons 41/42 with four nucleotides (TCTT) deletion, 7 (9.2%) had an A to T substitution at codon 17, 3 (3.9%) had frameshift codons 71/72 (insertion of A), 2 (2.6%) had an A to G substitution at position -28, and 2 (2.6%) had frame-shift codons 27/28 (insertion of C). The first two mutations accounted for 62 of the 76 beta-thalassemia mutations in this study. As to mutations in each individual with beta-thalassemia major, the incidence of compound heterozygotes of two different mutations was higher than that of homozygotes of a single mutation (60% vs 40%). Compound heterozygotes of C to T substitution at nucleotide 654 of IVS-2 and frameshift codons 41/42 with four-nucleotide deletion was the most common pattern of beta-thalassemia mutations in each individual (23.7%). Our results were unique compared with those from similar studies performed in southern China. Frequencies of beta-thalassemia mutations found in the current study were assessed and compared with frequencies found in previous studies conducted in northern and southern Taiwan.

Zinc deficiency decreases plasma level and hepatic mRNA abundance of apolipoprotein A-I in rats and hamsters

The influence of Zn deficiency on the plasma level as well as the hepatic and intestinal gene expression of apolipoprotein (apo) A-I was examined in rats and hamsters. Male Sprague-Dawley rats (8 wk old) and Golden Syrian hamsters (7 wk old) were assigned to three dietary treatments: Zn adequate (ZA, 30 mg Zn/kg diet), Zn deficient (ZD, <0.5 mg Zn/kg diet), and Zn replete (ZDA, ZD animals fed the ZA diet for the last 2 days). The dietary treatments lasted for 18 days for rats or 6 wk for hamsters. For the measurement of apoA-I mRNA abundance, hamster apoA-I cDNA was cloned from the small intestine. The full-length 905-base pair cDNA shared approximately 80% similarity with the human, rat, and mouse apoA-I cDNAs. Hepatic and plasma Zn levels were reduced in ZD animals but normalized in ZDA rats and increased in ZDA hamsters compared with ZA animals. Zn deficiency reduced plasma apoA-I and hepatic apoA-I mRNA levels 13 and 38%, respectively, in ZD rats. The 2 days of Zn replenishment raised plasma apoA-I and hepatic apoA-I mRNA levels in ZDA rats by 34 and 28%, respectively, higher than ZA rats. Similarly, these levels were decreased by 18 and 25%, respectively, in ZD hamsters but normalized in ZDA hamsters compared with ZA hamsters. In contrast to the alterations of hepatic apoA-I mRNA levels, neither Zn deficiency nor subsequent Zn repletion produced alterations in the intestinal apoA-I mRNA abundance. Data from this study demonstrated that Zn deficiency specifically decreases hepatic apoA-I gene expression, which may at least be partly responsible for the reduction of plasma apoA-I levels.